Golden bromination: A highly efficient and mild AuCl3‐catalyzed bromination of aromatic rings with N‐bromosuccinimide (NBS) has been developed. This method works with a low catalyst loading (down to 0.01 mol %) and can be combined with transition metal catalyzed transformations to deliver various aryl products.

Myelin basic protein (MBP) is an important component of the myelin sheath surrounding neurons and it is directly affected in demyelinating diseases. MBP contains a relatively large number of post-translational modifications (PTMs) which have been reported to play a role in multiple sclerosis while MBPs from lower vertebrates have been reported to be incapable of inducing multiple sclerosis or allergic encephalitis. This study reveals the extent of differences in PTM patterns for mammalian and non-mammalian MBPs. This included intact mass and de novo sequence analysis of approximately 85% of rattlesnake MBP, the first reptile MBP to be characterized and of bovine MBP. We identified 12 PTM sites in the five bovine MBP charge components which includes both previously reported and novel modifications. The most notable modification is an acetylation of lysine 121. Other modifications found in bovine MBP include N-terminal acetylation in components C1, C2, and C3; Oxidation of methionine 19 in all five components; All charge isomers had both a mono- and di-methylated (symmetric) arginine at position 106; Deimination in arginines 23 and 47 was found only in component C8b; Deimination of arginine 96 and deamidation in glutamine 102 was found in components C2, C3, C8a, and C8b; Phosphorylation in threonine 97 was restricted to charge components C2 and C3; Deimination in arginine 161 was only found in component C3; Deamidation of glutamine 120 was only observed in C1. All four deiminated arginines and one acetylated lysine were first experimentally revealed in this study for bovine MBP. Mascot database searching combined with de novo sequence analysis of rattlesnake MBP provided more than 85% sequence coverage. A few PTMs were also revealed in rattlesnake MBP: Mono- and dimethylated Arg, Protein N-terminal acetylation, and deiminated Arg. Overall, snake MBP was found to undergo less modification than bovine MBP based on the mass heterogeneity of the intact protein, the bottom-up structure analysis, and the limited complexity of rattlesnake MBP chromatography. The combined data from this study and information from previous studies extend the known MBP PTMs and PTMs unique to higher vertebrates are proposed.

Goldene Bromierung: Eine hoch effiziente und milde AuCl3‐katalysierte Bromierung von aromatischen Ringen mit N‐Bromsuccinimid (NBS) wurde entwickelt. Die Methode benötigt nur geringe Katalysatormengen (bis 0.01 Mol‐%) und kann mit übergangsmetallkatalysierten Reaktionen zur Synthese vielzähliger Arylprodukte kombiniert werden.